1. Field
One embodiment of the invention relates to an information processing apparatus in which video decoding processing for decoding a compressed and encoded video stream is achieved by software, and a video decoding method thereof.
2. Description of the Related Art
As standard technologies for encoding a video stream, H.261 and H.263 of the International Telecommunication Union Telecommunication Standardization Sector (ITU-T), Moving Picture Experts Group (MPEG)-1, MPEG-2, and MPEG-4 of the International Organization for Standardization (ISO), and the like, have been developed. As a next-generation video encoding method in which the technologies such as H.261 to H.263, MPEG-1 to MPEG-4, and the like have been succeeded, and further developed, there is the H.264 which has been standardized by the ISO and the ITU jointly. In the H.264, a deblocking filter for relieving a distortion generated at a block boundary is used as one of filters in loop, which enhances a picture quality improvement effect at a low bit rate particularly (refer to ITU-T Recommendation H.264 (2003), “Advanced Video Coding for generic audiovisual services”|ISO/IEC 14496-10: 2003, “Information technology, Coding of audio-visual objects—Part 10: Advanced video coding”, and H.264/AVC textbook (Impress Communications Corporation)).
On the other hand, personal computers having the same AV functions as those of audio-video (AV) equipment such as digital versatile disc (DVD) players and TV devices have been developed. In such a personal computer, a software decoder which decodes a compressed and encoded video stream by software is used. By the use of a software decoder, it is possible to decode a compressed and encoded video stream by a processor (CPU) without dedicated hardware being provided thereto.
In an information processing apparatus such as the above-described personal computer, assume that video decoding processing according to standardization specifications based on the H.264 is achieved by software. In this case, a proportion of the throughput of the deblocking filter accounting the entire decoding processing is high. For this reason, real-time decoding processing is made unable to be in time when a load on an entire system is high, and there is possibility that defects are brought about in which frames are dropped, movement of an object is made extremely slow, and the like. In particular, in a battery-driven information processing apparatus, such as a notebook-type personal computer, an electric power consumption is made higher when a load is made larger in a battery-driving mode, which makes a driving time extremely short.